Diffusivity of individual adsorbed water molecules at an Fe2O3 − Hematite/Water interface under external electric-field conditions

Abstract

The dynamical properties of physically and chemically adsorbed water molecules at a pristine hematite-(001) surfaces have been studied by non-equilibrium ab-initio molecular dynamics in the constant-volume, constant-temperature ensemble at room temperature, under externally-applied, uniform static electric fields of increasing intensity. Significant alterations in the dipole moment and self-diffusion constant were found vis-à-vis zero-field conditions, as well as shifting of the probability distribution of individual molecular self-diffusivities. For instance, application of static fields was found to increase the self-diffusion of water molecules at the α-hematite Fe2O3 surface, effectively due to some extent of ‘dipole-locking’ in the direction of the applied field.